Spinning devices for open-end rotor spinning machines are known.
For example, German Patent Publication DE 197 08 944 A1 discloses an open-end spinning machine with a spinning rotor, having a rotor shaft supported on a support disk bearing and a rotor cup that rotates in a rotor housing, that can be closed by means of a cover element and can be charged with a vacuum.
German Patent Publication DE 39 42 402 C2 discloses a similar spinning device. With this known spinning device, the rotor shaft of the rotor is also rotatably seated in two wedge gaps of a support disk bearing, and a tangential belt extending over the length of the machine acts on it. In this case the tangential belt simultaneously drives all spinning rotors of a side of the machine.
On the side opposite the wedge gaps, an expander roller is assigned to each rotor shaft that loads the tangential belt in the direction of the rotor shaft. The expander roller is seated, freely rotatable on a shaft of a two-armed expander roller holder that is pivotable around an axis extending parallel with respect to the axis of rotation of the expander roller and is loaded by means of a spring element. Moreover, the expander roller holder is connected via a pressure lever system with an actuating lever that when acted upon during the run-up of the spinning rotor results in an increase of the pressure force of the tangential belt against the respective rotor shaft.
This known spinning device has a pincer-like rotor brake, the ends of whose pincer arms are equipped with brake linings. The pincer arms are maintained in the opened state by a hoop spring or the like and can be applied to the rotor shaft by means of a brake gear.
Here, the rotor brake and the expander roller are connected via a common actuating mechanism in such a way that when the spinning device is opened, i.e. when the cover element is pivoted away from the rotor housing, the expander roller is automatically lifted off the tangential belt against the force of the spring element resting on it, and the rotor brake is closed. In this way the spinning rotor is dependably braked to a stop.
The above described spinning devices have been in actual use and have been employed in large numbers in the textile industry for quite a while.
However, under rare exceptional conditions, for example in the case of a defect in the tangential belt or unbalanced rotation of a spinning rotor, it can happen that the spinning device is charged with internal forces which, for example, results in the expander roller suddenly jumping up. In rare cases these internal forces can lead to the spinning device being opened before the spinning rotor has stopped which is not without danger for the operators.